The present invention relates to printers, scanners and fax machines, and more particularly, to an automatic document feeder that is more versatile in terms of the size of sheets it can handle and which ensures that outputted sheets do not fall out of a partial length output tray.
Over the past several years, combination printer, scanner and fax machines have become commercially successful. They can be attached to a personal computer and function as a traditional printer for printing high quality text and/or graphics on a suitable print medium, usually paper sheets. The printing may be reliably and economically accomplished utilizing black and/or color inkjet printer cartridges. These combination machines can also scan documents fed into the same so that text and/or graphics on the documents can be digitized and inputted into the personal computer for storage and/or further manipulation. Finally, these combination machines can scan documents fed into the same so that text and/or graphics on the documents can be sent via modem and telephone systems to other parties. In some cases these combination machines can function as low volume copiers by permitting text and/or graphics on a document fed into the machine to be scanned and then to immediately thereafter be printed on a clean sheet from an input paper tray. One example of a combination printer, scanner and fax machine with the foregoing capabilities is the OfficeJet (Trademark) desktop unit manufactured and sold by HEWLETT-PACKARD COMPANY, the assignee of the present application. See for example U.S. Pat. No. 5,833,381 granted Nov. 10, 1998 and assigned to HEWLETT-PACKARD COMPANY. In this type of combination machine individual sheets are fed in a unidirectional manner from an input side of the device, through the device, to an output side of the device.
Recently flat bed scanners have become popular peripheral devices for use with personal computers. Typically a document is placed flat on a large horizontal glass or transparent plastic platen and a scanning head reciprocates beneath the transparent platen to generate a very high resolution digital image of text and/or graphics on the document for subsequent computer processing or faxing. In co-pending U.S. patent application Ser. No. 09/041,844 filed Mar. 12, 1998 of A Justine Worley, assigned to HEWLETT-PACKARD COMPANY, and entitled MODULAR AUTOMATIC DOCUMENT FEEDER FOR A FLAT BED INPUT DEVICE, now U.S. Pat. No. 6,022,012 granted Feb. 8, 2000, there is disclosed an automatic document feeder xe2x80x9cADFxe2x80x9d) for sequentially loading and unloading single sheets over a flat bed scanner. A main chassis carries the active components of the ADF including paper pick and drive mechanisms for delivering sheets to and from a flat bed scanner, motors and transmissions for driving the pick and drive mechanisms, a document backing assembly and an electronic controller The main chassis also includes a substantially vertical document input tray. A lower chassis of the ADF includes a low-height form factor, substantially vertical, i.e. inclined, output tray, using paper stiffness caused by a predetermined bending of the outputted sheets to cause the sheets to be self-supporting. Documents are individually fed downwardly and forwardly from the input tray, in a landscape orientation, onto the transparent platen of the scanner, which scans each document moving in a direction transverse to the paper feed direction. After the completion of the scanning operation, each document is fed rearwardly and upwardly into the inclined output tray. An ink jet or laser printer can be provided beneath the flat bed scanner, The aforementioned ADF does not utilize a scroll-type sheet feed mechanism It pushes each page instead of relying on a belt-type advance mechanism.
The aforementioned ADF is advantageously configured to be hingedly mounted to a flat bed scanner to provide a multi-function product that can scan, fax, copy and print. However, problems have arisen with regard to its sheet handling capabilities. More particularly, scanning is designed around an A/A4 scan zone in a landscape orientation only, thus preventing users from scanning and copying over-sized print media, such as legal and B-size sheets. Furthermore, if over-sized sheets are fed into the output tray in portrait fashion, one or more of the sheets can end up being pushed out of the tray onto the desktop or floor.
Accordingly, it would be desirable to provide an ADF with an improved document handling capability.
It is another object of the present invention to provide an ADF that operates in a fashion that reduces the tendency for over-sized documents to fall out of the output tray when fed into the same in portrait orientation.
It is another object of the present invention to provide a combination ADF and flat bed scanner designed to accommodate both A/A4 sized documents fed in landscape orientation and over-sized documents fed in portrait orientation.
It is still a further object of the present invention to provide a method of ejecting media sheets from an ADF in a manner that reduces the tendency for the sheets to fall out of its output tray.
Still another object of the present invention is to provide a method of scanning over-sized media sheets fed by an ADF in portrait orientation to a scanner that normally scans standard-sized media sheets fed thereto in landscape orientation.
In accordance with one aspect of the present invention, an automatic document feeder (ADF) has a paper path that starts with an input tray, leads to an operational station such as a scanner, and then ends with a substantially vertical output tray. The ADF has a mechanism for picking off an individual media sheet from a stack of sheets in the input tray and propelling the sheet to the operational station where a function is performed on the sheet. Thereafter the ADF propels the sheet partially into the output tray, and momentarily stops or reverses the direction of travel of the media sheet before finally driving the entire sheet into the output tray. This ensures that if the topmost sheet in a stack in the output tray is lifted up by the sheet being driven into the output tray, the topmost sheet will fall back down to a rest position in the output tray and will not spill out of the output tray.
According to another aspect of the present invention, the combination ADF and scanner is operated so that it can automatically detect whether a standard-sized sheet of media is being fed into the scanner in landscape orientation or an over-sized sheet of media is being fed into the scanner in portrait orientation. In the case of the latter, first and second portions of the over-sized sheet are successively registered over the transparent platen of the scanner and scanned. The over-sized sheet is thereafter ejected from the scanner into an output tray. The resulting digital images of the first and second portions of the over-sized sheet are rotated, stitched together by a control circuit using software and/or firmware algorithms and the complete image of the oversized sheet is stored in a memory, faxed or printed.